Lime soap dispersants and compositions containing them

ABSTRACT

ALKYLBENZYL DI-LOWER ALKYLAMMONIO ALKANE-1 SULFONATES HAVING THE FORMULA   R-C6H4-CH2-N(+)(-R1)(-R2)-(CH2)N-SO3-   WHEREIN R IS A STRAIGHT OR BRANCHES CHAIN ALKYL GROUP HAVING 8 TO 24, PREFERABLY 10 TO 18, CARBON ATOMS; R1 IS AN ALKYL GROUP HAVING 1 TO 6 CARBON ATOMS; R2 IS AN ALKYL GROUP HAVING 1 TO 6 CARBON ATOMS; AND N IS AN INTEGER OF FROM 1 TO 4, PREFERABLY 2 OR 3. THESE COMPOUNDS HAVE EXCELLENT SCUM-DISPERSANT PROPERTIES AND ARE EFFECTIVE IN SOLID, GRANULAR, BAR, OR LIQUID SOAP COMPOSITONS TO REDUCE LIME-SCUM FORMATION. COMPOSITIONS COMPRISING HIGHER FATTY ACID SOAPS AND THE ALKYLBENZYL, DI-LOWER ALKYLAMMONIO ALKANE-1 SULFONTAES ARE DESCRIBED. DESIRABLE RESULTS ARE OBTAINED WHEN THE RATIO OF SOAP TO ZWITTERIONIC, BY WEIGHT, IS FROM 3:1 TO 100:1.

vU.S. Cl. 252-117 United States Patent ABSTRACT OF THE DISCLOSURE Alkylbenzyl di-lower alkylammonio alkane-l sulfonates having the formula wherein R is a straight or branched chain alkyl group having 8 to 24, preferably to 18, carbon atoms; R is an alkyl group having 1 to 6 carbon atoms; R is an alkyl group having 1 to 6 carbon atoms; and n is an integer of from 1 to 4, preferably 2 or 3. These compounds have excellent scum-dispersant properties and are effective in solid, granular, bar, or liquid soap compositions to reduce lime-scum formation. Compositions comprising higher fatty acid soaps and the alkylbenzyl di-lower alkyl ammonio alkane-l sulfonates are described. Desirable results are obtained when the ratio of soap to zwitterionic, by weight, is from 3:1 to 100:1.

This is a division of application Ser. No. 74,496, filed Sept. 22, 1970, now Pat. No. 3,660,470.

This invention relates to alkylbenzyl di-lower alkyl ammonio alkane sulfonates, and to soap-based detergent compositions containing them.

Detergent compositions based on conventional watersoluble soaps have many desirable properties, which render them at least highly competitive with detergent compositions based on other organic detergents. However, they have the well-known failing that in hard water insoluble soaps are formed, and these tend to flocculate, especially in the conditions of the rinse, to form what is often known as lime scum. This tends to be deposited either on fabrics which have been washed, where in effect it constitutes dirt, or on the vessels in which the washing and rinsing is carried out, for example as deposits on washing machines, or as bathtub ring. In the development of washing products, this failing has generally been countered either by making compositions based on synthetic detergents and containing no soap or only minor amounts of soap, or by adding agents, often known as lime soap dispersants, to soap compositions. These agents either prevent the formation of insoluble lime soaps, or prevent such soaps from flocculating, so that they are flushed away with the washing or rinsing liquid and do not adhere to fabrics or to the surfaces of the washing vessels.

It has now been found that certain novel zwitterionic compounds, derived from alkylbenzeues such as the socalled detergent alkylates, have excellent scum dispersant properties when combined, even in small proportions, with soap. They also improve the sudsing of soap products, by lowering the concentration required just to form suds in hard water, such a concentration being the concentration when soap first becomes available for cleaning articles.

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The new compounds are alkylbenzyl di-lower alkylammonio alkane-l sulfonates and have the formula:

wherein R is a straight or branched chain alkyl group having 8 to 24, preferably 10 to 18 carbon atoms; R is an alkyl group having 1 to 6 carbon atoms; R is an alkyl group having 1 to 6 carbon atoms; and n is an integer of from 1 to 4, preferably 2 or 3.

The invention also embraces detergent compositions comprising water-soluble soap and a compound as defined above.

Preferably, the zwitterionic compounds are those where R and R are each methyl or ethyl radicals. It is preferred to use those compounds wherein R is straightchained. The zwitterionic compounds can be based on alkylbenzene mixtures, such as most commercial detergent alkylates, which contain a mixture of alkyl benzenes of mean chain length within the above ranges.

The zwitterionic compounds of the invention can be conveniently made. One method is to form the alkylbenzyl chloride, e.g., by reaction in acetic acid of an alkylbenzene with formaldehyde and hydrogen chloride in the presence of zinc chloride, and to treat this compound with the appropriate dialkylamine to form the alkylbenzyl dialkylamine.

The resulting tertiary amine can be reacted for instance with a halo-alkane sulfonate, typically Cl(CH SO Na where n has the meaning defined above, or, for the compounds where n is 3 or 4, with propaneor butane sultone. Other preparative routes will occur to those skilled in the art and may be selected on grounds of convenience or economic advantage. For instance, it may be preferred to attach the alkane sulfonate group to the amino nitrogen and there after attach the alkylbenzyl radical.

The water-soluble soaps which can be used in the detergent compositions of the invention are the higher fatty acid soaps normally used for Washing, for instance the alkali metal, especially sodium or potassium, salts of fatty acids having from 8 to 24, especially 10 to 18 carbon atoms. The soaps can be made by direct saponification of natural oils and fats, such as tallow, palm oil, lard, greases, coconut or palm kernel oils and many others, or they can be made by neutralization of fatty acids derived from such oils and fats or from those made synthetically or derived from petroleum and like sources. Soaps from natural oils and fats, or from fatty acids derived from them, will be predominantly straight-chained. The synthetic fatty acids or those from petroleum sources can be straightor branch-chained. Preferred soaps are those made from mixtures of tallow, grease or palm oils to provide the longer chain, e.g., C fatty acid residues and coconut or palm kernel oil to provide shorter chain, e.g., C fatty acid residues.

The zwitterionic compounds of the invention can be present in any proportion relative to soap effective to provide lime soap-dispersing properties, but are normally present in relatively small proportions. Desirable results are obtained when the ratio of soap to zwitterionic, by weight, is from 3:1 to :1, especially from 10:1 to 20:1.

The lime soap-dispersing properties of the zwitterionic compounds of the invention can be employed to advantage by adding the compounds to a wash liquor, before or when the soap is added or before the washing process is begun. Ordinarily, the zwitterionic compounds are incorporated into a soap composition, which can be a solid, gr'anular, in bar form or a liquid. Mixtures of the zwitterionic compounds of the invention can be suitably employed. An alkaline builder salt can be included. The new compounds are particularly valuable as a component of granular soap products, especially built soap powders intended primarily for washing clothes. Such products can contain, in addition to the soap and zwitterionic compound, water-soluble alkaline builder salts. Suitable builder salts include alkali metal silicates, carbonates, phosphates and polyphosphates, borax, organic sequestering agents such as sodium nitrilotriacetate, ethane-l-hydroxy-l, l-diphosphonates and the like. Bleaching agents such as sodium perborate or percarbonate can be present Minor components such as dyes, perfumes, soil-suspending agents such an carboxymethyl cellulose, enzymes, tarnish inhibitors, dust-surpressing agents, stabilizers for the bleaching agents and/or the enzymes and the like can also be employed.

The invention is illustrated by the following examples.

EXAMPLE I Preparation of 3-(dodecylbenzyl dimethylammonio) propane-l-sulfonate 111 gms. of p-chloromethyl dodecylbenzene and 170 gms. of dimethylamine were charged into an autoclave provided with heating and stirring means. The mixture was heated in the closed autoclave, with stirring so that the temperature reached 155 C. over a period of 2 hours. After cooling the reaction mix separated into two layers. The upper layer was separated, washed with water and dried, and yielded 69 gms. of dodecylbenzyl dimethyl amine of purity about 98%.

30.3 gms. of this tertiary amine, 12.2 gms. propane sultone and 168 gms. of acetone were heated, with stirring, under reflux for 3 /2 hours. Solid which separated was filtered and washed with acetone and dried at 60 C. The filtrate was treated with a further 1.2 gms. of propane sultone and the solid which formed was filtered etc. as above. This was repeated. The total yield was 35.7 gms. of the desired compound, B-(dodecylbenzyl dimethylammonio) propane-l-sulfonate.

EXAMPLE II Scum dispersant effect A 1%% solution of soap in soft water was prepared, and arrangements provided so that air could be bubbled through it to form foam, which was carried over by the air current into a vessel containing hard (515 parts per million as CaCO water, wherein the foam was quenched. By this treatment, lime soap was for-med in flocculated form in the hard water. The water poured through a 100 mesh BSS sieve and the collected fiocculated lime soap dried and Weighed. Addition of scum dispersants to the soap solution reduced the weight of flocculated lime soap formed.

In the test, soap alone gave 0.27 gm. fiocculated lime soap. Soap with 10% by weight of the soap of 3-(dodecylbenzyl dimethylammonio) propane-l-sulfonate, prepared according to Example I, gave 0.01 gm. of liocculated lime soap indicating almost complete scum dispersion.

EXAMPLE III 1.9% solutions of soap in de-ionized water were prepared, containing in addition quantities of 3-(dodecylbenzyl dimethylammonio) propane-I-sulfonate (C sultaine) and of 3- (nonylbenzyl dimethylammonio) propanel-sulfonate (C sultaine). Each solution was placed in a water bath to maintain its temperature at 55 C. and nitrogen was bubbled through at a fixed rate. The foam formed was carried over for a set time into a vessel containing hard (515 parts per million as CaCO water, wherein the foam was quenched. The water was poured through a weighed 200 mesh BSS sieve, and the flocculated lime soaps retained determined, after drying, by re-Weighing the sieve. Results obtained were:

Weight of floeculated lime soap retained, g.

Weight ratio 0;; suJtaine C sultaine Soapzsultaine:

50:1 0.0037 0. 0054 20:1 0. 0019 0. 0054 10; 1 0. 0005 0. 0027 6:1 0. 000? 0. 0016 3: 1 0. 0018 0. 0012 No sul taine 0. 024 0. 025

EXAMPLE IV A heavy duty household soap composition A was prepared consisting of:

tallow; 10% coconut.

A comopsition B consisted of 95.2 parts of composition A and 4.8 parts of 3-(dodecylbenzyl dimethylammonio) propane-l-sulfonate, derived from commercial linear dodecylbenzene. Solutions of these compositions of concentration 0.25% by weight, were made up in hard water (256 parts per million hardness as CaCO in a Hoover Mark III washing machine and agitated for 30 seconds at 54 C. The agitator was stopped and after 30 seconds a black Perspex plate was dipped into the solution for 5 second and withdrawn through any scum present on the surface of the liquid. The plate was examined visually for adherent scum. The solutions of composition A left visible scum on the black plates, while those of composition B left no scum.

Similar results are obtained when the sodium tripolyphosphate of composition B is replaced in whole or in part by sodium carbonate; borax; trisodium nitriloacetate or sodium ethane-l-hydroxy-l,l-diphosphonate in that scum formation is minimized.

EXAMPLE V When increments of the compositions of Example IV were added to 39 litres of water in the same washing machine it was found that 105 gms. of composition A were required just to form stable suds, compared with 42 gms. of composition B.

What is claimed is:

1. A detergent composition consisting essentially of a water-soluble soa-p of a fatty acid having from 8 to 24 carbon atoms; and a zwitterionic lime soap-dispersing compound having the formula wherein R is an alkyl group of from 8 to 24 carbon atoms, R and R are each alkyl of from 1 to 6 carbon atoms and n is an integer of from 1 to 4; the ratio by weight of said soap to said zwitterionic lime soap-dispersing compound being from 3:1 to :1.

2. The detergent composition of claim 1 wherein in the zwitterionic lime soap-dispersing compound R is an alkyl group of from 10 to 18 carbon atoms.

3. The detergent composition of claim 1 wherein in the zwitterionic lime soap-dispersing compound R is an alkyl group of from 10 to 18 carbon atoms and R and R are each methyl or ethyl.

4. The detergent composition of claim 1 wherein in the zwitterionic lime soap-dispersing compound R is an alkyl group of from 10 to 18 carbon atoms, R and R are each methyl or ethyl and n is 2 or 3.

5. The detergent composition of claim 1 wherein the zwitterionic lime soap-dispersing compound R is a straightchain alkyl of 12 carbon atoms, R and R are each methyl and n is 3.

6. The detergent composition of claim 1 wherein the soap is a mixture of soaps containing C to C fatty acid residues Irom tallow, grease or palm oil and C to C fatty acid residues from coconut or palm kernel oil.

7. The detergent composition of claim 1 wherein the ratio by weight of soap to zwitterionic compounds is from 10:1 to 20:1.

References Cited UNITED STATES PATENTS 6 3,280,179 10/1966 Ernst 2521l7 X 2,699,991 1/1955 Stayner 252391 X 2,697,656 12/1954 Stayner 252-392 X 2,129,264 9/1938 Downing et al. 260 -501.12 X

FOREIGN PATENTS 704,554 2/1968 Belgium 260567.6 N 1,217,393 12/1966 Germany 260513 N 1,087,415 10/1967 Great Britain 252-l17 1,084,739 9/1967 Great Britain 260-501.13

LEON D. ROSDOL, Primary Examiner D. L. ALBRECHT, Assistant Examiner US. Cl. X.R. 

